1. Field of the Invention
The present invention relates to a printing apparatus and a driving method of a liquid ejecting head used therefore.
2. Description of the Related Art
An ink jet printing apparatus (hereinafter, also referred to as a “head”) for ejecting ink so as to print is known as a liquid ejecting head. In this type of head, for example, a head continuously ejecting pressurized ink from a nozzle and causing the pressurized ink to oscillate so as to produce liquid droplets is known. In this head, ink droplets unused for printing an image are electrically charged by a charging electrode and deflected in a flying direction thereof by a deflecting electrode so as to retrieve them. On the other hand, ink droplets used for printing an image go straight and land on a print medium without being charged and deflected so as to form an image. In a printing apparatus being capable of quickly printing at a high quality, it is necessary for a large number of nozzles to be integrated at a high density. If the above described charging electrode is arranged with respect to each of the large number of nozzles, respectively, the same number of control circuit outputs for the charging electrodes and wirings for connecting them to the charging electrodes as that of the nozzles are needed. A control voltage applied to the charging electrodes is generally a relatively high voltage, such as several tens to several hundreds of volts. Therefore, forming the electric wirings at a narrow pitch leads to problems such as it being difficult to ensure electrical insulation between the electric wirings, and voltage being induced in the wirings due to the mutual induction therebetween. In addition, the large number of the electric wirings connecting between the charge electrodes and the control circuit increases the costs for the electric wirings and the control circuit. To prevent these problems, Japanese Patent Laid-open No. S61-022958 (1986) discloses a technique to reduce mutual induction between wirings for charging electrodes by forming them alternately in opposite directions to broaden the pitch therebetween. Japanese Patent No. S58-016379 (1983) discloses a technique to reduce the number of wirings for signals and to supply electric power by forming charging electrodes, and shift registers and latch circuits of the control circuit corresponding to the charging electrodes, in a single semiconductor device.
In more highly integrated head, it is required to further broaden a pitch between wirings to reduce mutual induction therebetween. On the contrary, it is also required to reduce output points of a control circuit and connection points between the control circuit and charging electrodes to decrease the cost for controlling voltage applied to the charging electrodes.